Hundreds of tadpoles were released in B.C.'s Fraser Valley this week as part of an effort to protect Canada's most endangered amphibian.
Ocean Wise, a non-profit organization affiliated with the Vancouver Aquarium, said 1,400 Oregon spotted tadpoles have been transferred. More than 1,240 of those were released into what Ocean Wise calls a "suitable native habitat," while another 160 will be kept at the Greater Vancouver Zoo and released in the fall.
More than 21,000 of the species have been raised for release by the Vancouver Aquarium since 2010.
Oregon spotted frogs are named for the black spots with light centres located on their heads and backs. Fully grown, they measure between five and 10 centimetres in length.
The reddish brown, brown or green frogs look similar to Columbia spotted frogs, and until recently were thought to be the same species.
Columbia spotted frogs are more common, and live in B.C.'s Interior.
In B.C., Oregon spotted frogs are only known to breed in four scattered wetlands, all located within the Fraser Valley. There were once hundreds of thousands of the frogs, but their populations have dipped as much as 90 per cent from previous numbers, Ocean Wise said.
In the Fraser Valley, one of the major causes of depletion is industrial activity, including the draining of wetlands for agriculture. They have to compete with bullfrogs and green frogs, non-native species from eastern Canada, as well as predatory fish, for habitat and food. Invasive plants can also impact their habitat.
They're now extinct in California, endangered in B.C. and Washington state, and at risk in Oregon.
The Vancouver Aquarium is part of the Oregon Spotted Frog Recovery Team, which includes biologists, land managers and provincial ministries, that co-ordinates efforts to help recover the frog populations.
The aquarium is also involved in the release of tadpoles from endangered northern leopard frogs.
